Adsorbate electric fields on a cryogenic atom chip.

We investigate the behavior of electric fields originating from adsorbates deposited on a cryogenic atom chip as it is cooled from room temperature to cryogenic temperature. Using Rydberg electromagnetically induced transparency, we measure the field strength versus distance from a 1 mm square of yttrium barium copper oxide (YBCO) patterned onto a yttria stabilized zirconia chip substrate. We find a localized and stable dipole field at room temperature and attribute it to a saturated layer of chemically adsorbed rubidium atoms on the YBCO. As the chip is cooled towards 83 K we observe a change in sign of the electric field as well as a transition from a localized to a delocalized dipole density. We relate these changes to the onset of physisorption on the chip surface when the van der Waals attraction overcomes the thermal desorption mechanisms. Our findings suggest that through careful selection of substrate materials, it may be possible to reduce the electric fields caused by atomic adsorption on chips, opening up experiments to controlled Rydberg-surface coupling schemes.

Persistent supercurrent atom chip.

Rubidium-87 atoms are trapped in an Ioffe-Pritchard potential generated with a persistent supercurrent that flows in a loop circuit patterned on a sapphire surface. The superconducting circuit is a closed loop made of a 100 microm wide molecular-beam epitaxy-grown MgB2 stripe carrying a supercurrent of 2.5 A. To control the supercurrent in the stripe, an on-chip thermal switch operated by a focused argon-ion laser is developed. The switch operates as an on/off switch of the supercurrent or as a device to set the current to a specific value with the aid of an external magnetic field. The current can be set even without an external source if the change is in the decreasing direction.

Yield of bronchial forceps biopsies in addition to nasal brushing for ciliary function analyses in children.

BACKGROUND: The diagnosis of primary ciliary dyskinesia (PCD) is unlikely, if ciliary beat frequency (CBF) is normal. The aim of this study was to test the diagnostic value of an additional bronchial biopsy in cases where nasal CBF are abnormal. PATIENTS, METHODS: In a paediatric bronchitis population nasal brush biopsies and bronchial forceps biopsies were taken. In both samples we measured CBF and compared results to nasal CBF of infants and children without respiratory disease. RESULTS: Patients with bronchitis (n = 31; 0.3 to 14.6 years; 10 girls) had a normal CBF in their nasal biopsies in 68 %, and in bronchial biopsies in 48 %, compared to the reference group (n = 72; 0.5 to 17.5 years; 23 girls). One patient had an abnormal nasal, but a normal bronchial ciliary activity. When cilia were beating at both sites (n = 14), nasal CBF agreed well with bronchial CBF (mean difference -0.78 Hz, 95 % confidence interval -1.81 Hz to 0.25 Hz). CONCLUSIONS: By adding the investigation of bronchial mucosa to the measurement of nasal CBF the diagnostic yield to exclude PCD was only improved from 68 % to 71 %. Consequently, if nasal ciliary activity is abnormal in infants and children with bronchitis, we do not recommend additional bronchoscopy to obtain another biopsy.

Impact of atmospheric deposition on the headworks of a wastewater treatment plant--a case study.

Specialized sampling equipment and ultra-clean analytical methodology were employed to quantify the concentrations or fluxes of mercury (Hg), cadmium (Cd) and polychlorinated biphenyl (PCBs) in ambient air, precipitation, runoff, sanitary sewer, and wastewater treatment plant (WWTP) influent. The relationship between the atmospheric deposition and runoff on controlled surfaces were explored for the three pollutants. The impact of the atmospheric deposition and runoff to the headwork loading of the WWTP were investigated. Atmospheric deposition was found to be the primary source of the mass of Cd, Hg, and PCBs in runoff from the controlled surfaces. Neither atmospheric deposition nor the runoff was the main sources of the three pollutants to the Detroit Wastewater Treatment Plant (WWTP). Wet weather flow contributes the main portion of the Cd, Hg, and PCBs loading to the WWTP.

Mechanisms for LEPR-mediated regulation of leptin expression in brown and white adipocytes in rat pups.

To investigate the underlying mechanisms for leptin receptor (LEPR)-mediated regulation of leptin gene (Lep) expression in brown (BAT) and white (WAT) adipose tissue and resultant effects on plasma leptin concentrations (plasma-LEP), we examined effects of sympathetic nervous system (SNS) activity, caloric balance, and body fat content on leptin mRNA levels in BAT and WAT in 10-day-old rat pups segregating for Lepr(fa). In mother-reared pups, Lep mRNA levels were fa/fa > +/fa = +/+ in BAT and was fa/fa > +/fa > +/+ in WAT. The genotype effects on Lep expression in BAT and plasma-LEP were virtually eliminated when the differences in SNS activity between fa/fa and +/fa pups were equalized by artificial rearing of pups under thermoneutral conditions with or without oral norepinephrine (NE) administration. NE administration alone had little effect on the Lepr(fa)-dependent stratification of Lep expression in WAT. BAT-Lep mRNA was the main determinant of plasma-LEP. Metabolic rate, a surrogate indicator of SNS activity, explained 87% of the variation in BAT-Lep mRNA (R(2) = 0.93), whereas caloric balance (40%) and body fat mass (6%) accounted for most of the variation in WAT-Lep mRNA (R(2) = 0.53). We conclude that feedback regulation of Lep expression in BAT is primarily via central nervous system-mediated effects of leptin on SNS activity, whereas the control of leptin expression in WAT is more likely via mechanisms not directly dependent on SNS activity.

Long-term effects of the endothelin(A) receptor antagonist LU 135252 and the angiotensin-converting enzyme inhibitor trandolapril on diabetic angiopathy and nephropathy in a chronic type I diabetes mellitus rat model.

Diabetic angiopathy is a serious problem in antidiabetic therapy. We wanted to investigate whether treatment with the endothelin(A) receptor antagonist LU 135252 or with the angiotensin-converting enzyme inhibitor trandolapril might prevent angiopathy in long-term type I diabetes mellitus. Six groups of male Wistar rats were investigated: untreated age-matched control rats, healthy controls treated with trandolapril (0.3 mg/kg), healthy controls treated with LU 135252 (100 mg/kg), untreated diabetic rats, and diabetic rats treated with either trandolapril or LU 135252. Rats were rendered diabetic by injection of streptozotozin. Duration of the disease was 6 months. Thereafter, rats were sacrificed, and hearts, kidneys, and a mesenterial loop were removed. Hearts and kidneys were processed histologically; the mesenterial loop was perfused with saline at constant pressure for investigation of microvessels using microvideoangiometry while treated with either 30 mM KCl, 1 microM acetylcholine, or 1 microM sodium nitroprusside. All diabetic rats developed hyperglycemia without differences among these three groups. Diabetic rats exhibited marked anemia, which was significantly antagonized by both treatments. The heart capillaries/muscle fibers ratio was decreased significantly in diabetic animals, which was prevented fully by both treatments. Renal glomerular diameter was increased in diabetic rats. This was significantly antagonized by LU 135252 but not by trandolapril. Deposition of homogeneous eosinophilic material within the glomeruli was nearly completely prevented by LU 135252. The acetylcholine-induced vasodilation in mesenteric microvessels was significantly attenuated in diabetic rats, which was significantly antagonized by both treatments. We conclude that both angiotensin and endothelin seem to contribute to the development of diabetic angiopathy and that, in addition to angiotensin-converting enzyme inhibition, blockade of endothelin(A) receptors may be an interesting new approach to antiangiopathic therapy.

Mutation in the leptin receptor (Leprfa) causes fat-storage-independent hyperleptinaemia in neonatal rats.

The plasma leptin concentration adjusted for fat mass is affected by mutant gene dosage in older animals segregating for Leprfa. Because the plasma of neonatal rats contains leptin, although their adipocytes contain virtually no triglyceride, we determined whether mutation dose-dependent differences in plasma leptin concentration exist before the postnatal onset of triglyceride storage. Plasma samples were obtained 10 min after birth of each rat pup and leptin concentration determined by radioimmunoassay. Plasma leptin in homozygous wild-type (+/+) pups was 1.6 +/- 0.2 ng/ml (n = 20) and 2.4 +/- 0.2 ng/ml in +/fa (n = 32) littermates (least-square means +/- SE, P < 0.05, two-way ANOVA with litter and genotype as factors). The corresponding values for +/fa (n = 21) and fa/fa (n = 15) littermates were 2.4 +/- 0.2 and, 4.0 +/- 0.3 ng/ml respectively (P < 0.001). Leprfa gene dose-dependent elevations in plasma leptin are, therefore, present at birth and constitute the only Leprfa-related phenotypic trait presently known to precede the onset of increased fat storage.

Deep venous thrombosis: an overview.

The patients at high risk of deep venous thrombosis are defined. Factors in the formation of intravenous thrombi are described. The roles of endothelium, formed elements, clotting factors, and their interrelationships are correlated. Diagnostic modalities and their application are described, and the commonly used medical and surgical therapies are specifically outlined.

Femoropopliteal bypass using externally supported polytetrafluoroethylene grafts. Early results in a multiinstitutional study.

A multiinstitutional retrospective study was undertaken to evaluate the externally supported PTFE graft to determine whether a nonkinking, noncompressible graft offers advantages in patency and limb salvage. We studied the results of 104 femoropopliteal arterial reconstructions performed on 99 patients between June 1981 and June 1983. The combined above-the-knee and below-the-knee cumulative patency rate at 2 years was 88 percent and the limb salvage rate was 97 percent. We found these results to be comparable to the patency typical of saphenous vein grafts and better than that of reinforced PTFE grafts. The improved patency is due to the lack of kinking and compressibility of the externally supported PTFE graft, as well as histologic evidence of excellent collagen infiltration which stabilizes the graft in position. A longer follow-up period is certainly needed to make definite recommendations, but our preliminary studies are encouraging.

Non-invasive evaluation of thoracic aneurysms.

Sixty-six patients with possible abnormalities of the thoracic aorta were examined by CT and the data compared with standard chest radiographs, angiography and, in most, with the surgical findings. Using contrast enhancement computed tomography was able to evaluate and differentiate between a tortuous aorta, an atherosclerotic aneurysm, and aortic dissection and extra-aortic masses. Distinguishing pathological features are discussed. In aortic dissections angiography may be necessary to delineate the site of the intimal tear. Long term follow-up of aortic dissections, especially Type III, is best done by CT. Aneurysmal rupture or leakage, as well as extension into the abdominal aorta, can easily be ascertained by this method.

Hemochromatosis heart disease: an unemphasized cause of potentially reversible restrictive cardiomyopathy.

Cardiac involvement in hemochromatosis typically results in congestive cardiomyopathy; a restrictive cardiomyopathy due to hemochromatosis is distinctly rare. A restrictive cardiomyopathy, which developed in the patient described in this report, was due to hemochromatosis which mimicked constrictive pericarditis clinically, echocardiographically and hemodynamically, and resulted in a thoracotomy for attempted surgical therapy. The fact that hemochromatosis represents the only cause of a restrictive cardiomyopathy that is potentially reversible by medical therapy makes early recognition of hemochromatosis heart disease important.

Abdominal aortic aneurysms: diagnostic review and new technique.

A new technique of computed tomography (CT) applied to the diagnosis of abdominal aortic aneurysms is described, and the experience in 58 patients is reviewed. In all instances the abdominal aorta was clearly demonstrated, even when wall calcification was absent. A series of 37 patients with abdominal aortic aneurysm underwent evaluation by physical examination, abdominal roentgenograms, and ultrasonic and CT scanning. Measurements of the transverse diameter at the point of maximal dilatation were compared with the measurements made at operation. CT not only confirmed the diagnosis in all patients but the measurements obtained by this technique were the most accurate, correlating extremely well with the true dimensions of the aneurysm. The addition of contrast enhancement to CT scanning allowed clear delineation of the aortic lumen and intraaneurysmal thrombus, not possible with any other method, including ultrasonography. The technique appears useful as a screening procedure and in the differential diagnosis of a tortuous abdominal aorta. Patients with a small aortic dilatation can be followed accurately by scanning.

Calcific pulmonic stenosis in adulthood: treatment by valve replacement (porcine xenograft) with postoperative hemodynamic evaluation.

Clinical and morphologic features are described in a 56-year-old man in whom severe, isolated pulmonic valve stenosis was treated by valve replacement with a porcine prosthesis. The calcific deposits were located on the ventricular aspect of the pulmonic valve, opposite the location (arterial aspect) of calcific deposits on stenotic aortic valves, and calcific deposits also were present in the tricuspid valve anulus.

[Hereditary angioneurotic edema. Clinical aspects, pathogenesis and therapy]. / Hereditäres angioneurotisches Odem. Klinik, Pathogenese und Therapie.

A family with hereditary angioedema is presented. In 4 members of the family the diagnosis was confirmed by decreased C1 esterase inhibitor levels. Clinical course and pathogenesis are described briefly. New ways of treatment are discussed, especially injection of purified C1 esterase inhibitor and stimulation of C1 esterase inhibitor synthesis by oral therapy with attenuated androgens.

Evaluation of lactate dehydrogenase isoenzyme patterns in serum of patients undergoing cardiac surgery.

Serial determinations of serum lactate dehydrogenase (LD) isoenzymes were performed in 50 patients undergoing cardiac surgery for coronary artery bypass and heart valve replacement. A sequence of LD isoenzyme patterns was established in the patients with uncomplicated recovery. These patterns served as controls for the detection of abnormal patterns associated with clinical complications. Perioperative myocardial infarction was detected in seven patients by a characteristic reversal of the LD1:LD2 ratio. These studies established that accurate determination of LD isoenzymes improved their diagnostic specificity. These isoenzymes were determined by (1) using the same technique for tissues and for serum samples, (2) applying a volume of serum containing a standard amount of enzymatic activity, and (3) making a clear separation, which allows accurate quantitation. This test can provide useful information to the surgeon for the evaluation of operative procedures and to the clinician for the appropriate management of the patient undergoing cardiac surgery.